A known method of making fiber preforms consists in superposing layers of two dimensional fiber fabric such as a cloth or a felt, and in interconnecting the layers by needling. For a part that is to be subjected to high mechanical or thermomechanical stresses, it is desirable to obtain bonding between the layers of a preform in order to avoid the part being damaged or destroyed by delaminating, i.e. by two of its layers coming apart.
Documents FR-A-2 557 550, FR-A-2 584 106, and FR-A-2 584 107 describe methods and installations for manufacturing needled fiber preforms, and respectively: non-cylindrical asymmetrical preforms; preforms comprising layers stacked flat; and circularly symmetrical cylindrical preforms. According to those documents, the preforms are made up of a plurality of wound or superposed layers formed by a tape or a strip of cloth. As the preform is built up, each new layer is needled to the underlying structure by using a set of needles extending across the entire width of the tape or the strip of cloth.
The above-mentioned methods and installations are suitable for making preforms of a general shape that is relatively simple, but they cannot be used for more complicated shapes.
An object of the present invention is thus to provide an installation which does not suffer from such a limitation and which consequently makes it possible to make fiber preforms that are complex in shape.